Cirkul is one of those bottles that sparks curiosity the moment you first use it. Unlike the best smart water bottle or best hydrogen water bottles, there’s nothing electronic here. Just a cartridge, a lid, and some surprisingly clever engineering.
So, how does it make the flavor? Where does the water go? What’s actually happening inside that cartridge?
I’ve cracked open more than a few Cirkul cartridges just to see the inner workings (don’t worry, they weren’t all wasted). So if you’re wondering what’s really happening every time you take a sip, let’s break it down.
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KEY FEATURES
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How Does the Cirkul System Work?
In short, Cirkul uses pre-filled flavor cartridges called Sip® cartridges. Each cartridge contains flavored liquid (some sweetened, some not), and it’s attached to a compatible Cirkul lid. This cartridge is connected to the piece in the center of the lid that controls how much flavor liquid passes through.
Then, when you sip, you generate negative pressure (basically, suction), which pulls the water up through the cartridge. But, and here’s the interesting part, the water doesn’t mix with the flavor until it reaches the lid. Nothing happens inside the bottle itself.
The Lid & Flavor Dial
The real engineering happens in the lid, which acts as a flavor gatekeeper with a built-in dial that lets you decide how much taste you want in your sip.
Here’s how it works:
- X (or zero level): flavor completely blocked. You’re just drinking plain water.
- 1-9: adjustable levels of flavor intensity.
- The “unofficial 10”: if you twist the dial a bit past 9, you can squeeze out even more flavor.
This dial is why cartridges last longer or shorter depending on your habits. For me, level 3 is the sweet spot, giving me about 120 ounces per cartridge. If I bump it up to level 5 or 6, that drops to maybe 70-80 ounces. The higher you crank it, the faster the flavor runs out.
When you adjust the dial, you’re opening or closing a tiny gap that controls how much flavor liquid seeps into the water stream. Tighten it fully (at “X”), and no flavor escapes. Loosen it, and the gap widens, letting in more flavor.
The lid has a few other neat tricks too. Inside the spout is a thin membrane that acts like a one-way valve. You can turn the bottle upside down with the cap open and not a single drop escapes, unless you squeeze the bottle, in which case the water flows freely. It’s a rare and useful feature that I spotted only in two other bottles I own.
There’s also a cap covering the spout. At first I tried prying it open with my fingernails. Then I noticed two little strips on the back that literally say press to open. When you do, the cap pops open almost by itself. Tiny details like this make me like this bottle even more.
How to Use Cirkul for the First Time?
Getting started with Cirkul is surprisingly simple. When your bottle and cartridges arrive, the first step is to snap the flavor cartridge into the lid. They come pre-connected, so you don’t have to wrestle with tiny pieces.
Next, pour plain water into the bottle. Screw the lid onto the bottle, making sure it’s snug but not over-tightened, and you’re ready to go.
Now, set the flavor dial. With ten levels of intensity, you can go from 0 (pure water) to 10 (full-flavor mode). I personally start around level 3-5 and adjust depending on my mood or how thirsty I am.
Then, simply sip. The water flows through the cartridge, picking up flavor as it goes. The beauty? You control how strong the taste is without ever touching the water itself.
The bottle is easy to wash by hand or on the top rack of the dishwasher.
Do You Just Throw Away Cirkul Cartridges?
You don’t actually have to throw away your Cirkul cartridges the moment you stop sipping. The company even sells an accessory called the Sip Safe – basically a little hard case where you can stash two cartridges for later.
But once you’ve cracked a cartridge open and started using it, the official advice is to finish it within 10 days. And honestly, I stick to that rule. Partly because the flavor weakens over time, but mostly because I don’t trust half-used cartridges just hanging around. Warm weather, moisture, and lingering sweetener are basically an open invitation for bacteria or mold.
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Jeremiah Kowalski
Hey there! I’m Jeremiah, the guy behind WaterBottleAdvisor.com. I used to have a bad habit of guzzling sodas while working remotely, but thanks to reusable water bottles, I’ve turned my hydration game around. After testing over 50 bottles, I’m here to help you find the perfect one to make staying hydrated a joy, not a chore. When I’m not reviewing bottles, you’ll likely find me scaling steep trails around the world, trusty water bottle in hand.
